IL34104A - Anchorage body for anchoring tendons with wedges - Google Patents

Description

nnn' oy o»m»a p.¾»yV pa'y Anchorage bod for anchoring tendons with wedges Antonio BRANDBSTINI C: 32427 The present invention relates to an anchorage body for anchoring tendons with wedges, such as strands. Known anchorage bodies for anchoring tendons with wedgee have a central passage for the tendon, at least one section of which passage widening conically from the inlet end to the outlet end in order to form a seat for wedges.

Such anchorage bodies for tendons, knoxm in various forms, do not fulfill all conditions as end anchorages inserted In the formwork or shuttering.

The main disadvantage of such known anchorage bodies resides in the fact that the inlet opening in the anchorage body is not adequately sealed, this leading to the wedge seats being fouled by grout, etc.

The present invention has for its object to provide an improved anchorage body whioh contributes to avoid the disadvantages of the known devices.

Accordin to the present invention there is provided an anchorage body for anchoring tendons with wedges having a central passage for the tendons, at least one section of which passage widening conically from the inlet ¾nk- to the outlet end in order to form a seat for wedges and presenting a projection at the inlet end of said passage, said projection forming a part integral with the remaining anchorage body and having also a passage for the tendon, the first sectio of the passage in said projection tapering conically in order to form a seat for a centering-and seallng-element to be inserted between tendon and 34104/2 anchorage body, a shoulder-like local constriction being provided between the conically tapering and the conically widening section of the passage, which shoulder serves as stop for the centering- and sealing-element.

The invention will be bette understood, and objects other than those set forth above will become apparent, when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein generally the same reference numerals or characters have usually been employed to denote the same or analogous elements, and wherein: Pig. 1 shows a longitudinal section through an end anchorage by means of an anchorage body according to the invention.

Fig. la is a front view of the anchorage according to Fig. 1.

Fig.2 shows a longitudinal section through .the inlet section of a similar anchorage.

Fig. 3 shows a section through the inlet opening of a further embodiment of an anchorage.

Fig. 4 and 5 show longitudinal sections through two anchorages in finished state, and Figs. 6 and 8 show longitudinal sections through the inlet portion of similar anchorages .

' When placing the tendon 1 and the end anchorages in a shuttering, the following must particularly be heeded: a) Care must be taken that no grout can penetrate into the which widens from the inlet end A to the oulet end B and conical space 3a which will later receive the wedges 3, either on the front side B of the anchorage body or above all on the later inaccessible rear side A thereof.

Furthermore, the following conditions should if possible also be heeded: b) The tendon 1 (together with sheathing la) should be exactly centered at the inlet point A in the anchorage body, so that when the tendon is later stressed, this centering remains true . c) The anchorage body 2 must be fixable in the correct position, immovable with respect to the shuttering or form-work 7, so that, during concreting, the position of the anchorage body remains unaltered and said shuttering or formwork may easily be removed after the concrete has hardened .

In the embodiments shown, conditions a) and b) are fulfilled (Figs. 1-5), in that the anchorage body has on projection which forms a its rear side A a/tubular extension 2a internally provided with a conical recess 2b, which tapers in direction B.

After the tendon 1, which may be -enveloped in a paper passing through the recess 2b and the sheathing la, has been inserted 0 n¼u%ularar%s¾'ient 2b from inlet sealing body 4 is pressed -i«-d-ij?€€*-i«fi 3 into said recessA By the deformation of the sealing body 4 due to the conical inner face of the anchorage body extension 2a, the inside of the sealing body lies tightly against the tendon 1, la and its outside tightly against the inner wall of the recess 2b of the anchorage body. In this way, a centering of the tendon .1 and a seal against the penetration of grout is obtained. A local constriction 2c of the conical recess 2b can prevent the penetration of the sealing body 4 into the wedge space 3a. The inner diameter of the constriction 2ς must however be considerably larger than the outer diameter of the tendon, since it must be possible to push said tendon through this constriction without difficulty.

Particularly when using strands as tendons, considerable thickenings are often formed- at the ends thereof due to cutting by means of cutting torches, which thickenings must be guided through the constriction 2c. A centering of the tendon by means of this constriction must therefore be omitted, for practical reasons.

The sealing body 4 may be composed of rubber, plastic material or even metal; it may also be provided with a longitudinal slit at least at one place over at least a certain length. Especially when using a sealing body composed of metal, the seal at point A can be "additionally.. reinforced--by-the. inte position of a sealing ring .5 (Fig.1,2) made of soft material. On the other hand, when using a sealing body 4 composed df comparatively soft material, a ring 5a consisting for example of two parts may be placed on the constriction 2c as centering means (Fig.3), before the seal 4 is pressed in. The sealing body 4 may be of any desired length. Fig.l shows by way of example a comparatively short body; the tendon here consists of a strand with a lubricating and rust-protection coating and a paper sheathing la. The tendon may however also pass through a rigid conduit (e.g. metal hose) lb (Fig. 2), the space between tendon and sheathing being grouted after stressing. The seal 4a between the conduit and the anchorage body 2,' 2a may in this case be constructed as shown in Fig.2, and it may also take over the function of a connecting piece, i.e. mav £e provided with another inlet opening 4b for the connection of the pipe for the grout .

The sealing body 4 may also be additionally glued to the conical inner face 2b. This inner face may have a rough surface for better adhesion.

Condition c) is also fulfilled by the present invention. To this end, the anchorage body 2 is securely connected (for example by screwing) to a holding sleeve 6 (Figs. 1-5). The shuttering or formwork 7 is for its part securely connected to the holding sleeve 6 by being pressed against the shoulder 6b of the holding sleeve 6 by means of the nut 6d. It is important that the holding sleeve 6 is not only securely, but also tightly connected to the anchorage body 2. It is shown that when .us.lag .a suitable plastic material, a multiple thread 6f is sufficient for the seal against g out penetrating into the wedge space 3a.

In order to increase the seal, the teeth of the thread or the surface 6b and 6g may be provided with thin fins which are pressed together when the holding sleeve >*■ xs screwed in and thereby improve the seal.

After the concrete has hardened, the holding sleeve 6 is removed, this being simplified by the cone 6a. The finished anchorage is shown in Fig. 4.

Fig. 5 shows the same anchorage when it is not to be fixed against a shuttering or formwork, but is to lie inside the concrete structure as so-called fixed anchorage.

In this case, the wedges 3 are from the beginning firmly seated in the wedge space 3a and the tendon will thereby be anchored . In order to secure the wedges 3, a cap 8 with spring 9 located inside the cap is screwed onto the anchorage body 2.

Fig. 6 shows the inlet portion of an anchoring body 2 in which the sealing shell 4- surrounding the tendon 1 sits on the outer surface of the extension 2a. The sealing shell 4 may be secured on the extension by means of any suitable mechanical means or by an adhesive. In the anchorage shown in Fig. 6 no centering element is provided for tendon 1..

Fig. 7 shews an anchorage similar to that of Fig. p with the only difference that the outer surface of the extension 2a of the anchorage body 2 is provided with a thread/for threading thereon the sealing shell 4.

Fig. 8 finally shows part of an anchorctg-e.-in _which the sealing shell 4 bears against the outer surface of the extension 2a of the anchorage body, whilst a centering means, e.g. a two-part centering cone 11, is provided between the tendon 1 and the wall of the conically inwardly tapering passage 2b of the extension 2a.

Claims (9)

1. An anchorage body for anchoring tendons with wedges having a oentral passage for the tendons, at least one section of which passage widening conically from the inlet end to the outlet end in order to form a seat for wedges and presenting a projection at the inlet end of said passage, said projection forming a part integral with the remaining anchorage body and having also a passage for the tendon, the first section of the passage in said projection tapering conically in order to form a seat for a centering-and sealing-element to be inserted between tendon and anchorage body, a shoulder-like local constriction being provided between the conically tapering and the conically widening section of the passage, which shoulder serves as stop for the centering- and sealing-element.

2. An anchorage body as defined in Claim 1, wherein it is provided with means to which a holding sleeve can be removably secured,

3. An anchorage body as defined in Claim 2, wherein said means consist of a thread provided at the outlet end, on which a holding sleeve is detachably screwable.

4. An anchorage body as defined in Claim 1, 2 or 3, wherein the passage is widened' ear the outlet opening and a thread for removably securing a holding sleeve is. formed as an internal thread in this part of the passage.

5. An anchorage body as defined in any one of the preceding claims, wherein the surface of the conically tapering section of the passage is roughened. '■

6. An anchorage body as defined in any one of the preceding claims, wherein an adhesive layer is provided on the surface of the conically tapering section of the passage.

7., An anchorage body as defined in any one of the preceding claims, wherein said projection forms a tubular extension of the anchorage body, the outer surface of said tubular extension forming a seat for attaching a sealing shell.

8. An anchorage body as defined in Claim 7, wherein a thread for connecting a sealing shell is provided on the outer surface o said tubular extension.

9. An anchorage body as defined in Claim 1, substantially as described with reference to the drawings. For the Applicants PARTNERS EHAiCB